Numberical and experimental investigations on an innovative, regeneratively heated radiant tube with compact dimensions

The presented, public funded research cooperation project of the Department for Industrial Furnaces and Heat Engineering at the RWTH Aachen University and the WS Wärmeprozesstechnik GmbH main aim is the development of an innovative, regeneratively heated radiant tube with compact dimensions. The main components are the I-shaped radiant tube with regenerators and an inner gas tube with 36 gas outlets over the entire tube length. Due to fuel-staging and a desired flameless combustion, low NOx-emissions are ensured. A high thermal efficiency is ensured by a regeneratively operated air preheating system. Ceramic honeycomb modules (regenerative module) are installed on both sides of the radiant tube in the furnace wall, which preheat the combustion air in alternating operation. By that, preheating temperatures of around 1050 °C are possible. Numerical simulations for different gas tube diameters were performed to figure out the most suitable diameter for a uniform temperature distribution at the radiant tube surface. With this information, a test model was developed and investigated in a test bench. The temperature homogeneity and the off-gas composition are the main parameters examined. In this paper, numerical and experimental results of the test model and the design of a prototype, based on the results of the test model, are presented.